This invention relates to a process wherein exhaust steam from a steam turbine operated by geothermal steam is condensed with an aqueous solution containing ferric chelate and the hydrogen sulfide in said geothermal steam is converted to free sulfur.
It is known from U.S. Pat. No. 4,123,506, dated Oct. 31, 1978, and U.S. Pat. No. 4,202,864, dated May 13, 1980, that geothermal steam containing H.sub.2 S can be purified by contacting the steam with a metal compound that forms insoluble metallic sulfides.
It is also known from U.S. Pat. No. 4,196,183, dated Apr. 1, 1980, that geothermal steam containing H.sub.2 S can be purified by adding oxygen and passing it through an activated carbon bed.
Various processes for hydrogen sulfide control in geothermal steam are outlined in the U.S. Department of Energy Report #DOE/EV-0068 (March 1980) by F. B. Stephens et al.
U.S. Pat. No. 4,468,929, dated Sept. 4, 1984, shows the use of ferric chelate solutions to remove H.sub.2 S from exhaust geothermal steam with direct or indirect contact of the steam with chelate solutions.